I get the noise part.
The thing is, in your home, people, pets, etc. produce CO2. Modern homes with good windows and weather stripping trap the CO2 inside the home. So, the home has a higher level of CO2 than the outside air. Therefore, if you're running the skimmer using air from inside the home, there is likely a build up of CO2 in that air that will suppress the pH. That's why a lot of people connect tubing to the skimmer air intake and put the other end outside...to get fresh (less CO2) air into the system thus increasing pH. That said, some have had success doing this, others have had minimal/moderate success and others have not seen a difference.
Three options to help increase pH.
1. Introduce outside air through the skimmer air intake. Pros - Free and cheap to do. Cons - May not work, potential for pesticides and other chemicals used by you or neighbors to be introduced into the tank.
2. Drip kalkwasser. Pros - Relatively inexpensive if done manually. Cons - Can get costly if you automate (dosing pump) and may not help.
3. CO2 scrubber. Pros - Many have reported good success with this. Cons - Can be costly and you have to replace the media.